The present invention is generally related to driver protection systems in automobiles. More specifically, the present invention is related to a motorized seat belt system.
Restraint systems such as motorized seat belt retractors (MSB) have become standard equipment in modern automobiles. Motorized seat belt retractors are widely used to protect passengers from the impact produced during a vehicle collision. Prior to a collision involving the vehicle, the MSB actuates a seat belt to protect the passenger. The MSB could be deployed because there are indications of an impending collision (an emergency situation), such as severe breaking or swerving of the vehicle, the dynamics of the vehicle indicate a potential rollover, or external sensor systems (e.g. radar, vision systems, etc) predict a high probability of a collision. The MSB could also be deployed at low force levels for comfort related reasons.
A motorized seat belt retractor includes an electric motor that operates to retract the seat belt in case of an emergency. The operation of the motor may be controlled by a signal generated by a microprocessor. As a result, there is the possibility of the motor operating and the MSB deploying in the event of a microprocessor failure. Avoiding inadvertent MSB deployment in the event of a microprocessor failure is a desired operational characteristic. Accordingly, there is a need for a cost efficient motorized seat belt system capable of preventing the inadvertent deployment of a motorized seat belt retractor.